Dual-Motor Powertrain With Seamless Multi-Ratio Planetary Shifting
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing electric powertrains for trucks and large vehicles face challenges such as high energy consumption, decreased power efficiency due to multiple gear steps, and limited gradeability due to lack of access to lowest gears, making them unsuitable for long-haul operations.
Innovation Solution
A powertrain design incorporating two electric motors, a transmission assembly, and a planetary gear with clutch assemblies that allow seamless gear shifts between multiple ratios without torque interruption, utilizing a shiftable planetary gear to provide optimal torque and efficiency across varying driving conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple gear steps are used to provide various gear ratios, then the electric motors can operate efficiently across different speeds, but power efficiency decreases due to multiple gear steps
Solution Approach 1:
The patent implements continuous torque delivery during gear shifts by using a planetary gear system where the sun gear remains continuously connected to the carrier through planet gears. This eliminates torque interruption and maintains continuous power transmission, resolving the contradiction between providing multiple gear ratios and maintaining power efficiency.
Solution Approach 2:
The patent combines multiple gear ratios into a single planetary gear stage by utilizing the inherent properties of the planetary gear system. The sun gear, ring gear, and carrier can be selectively locked or unlocked to provide different gear ratios (including reverse gear) in a single compact stage, reducing the number of separate gear steps and improving power efficiency.
2Volume of moving object
If a single planetary gear stage is used, then the structure is compact and space is saved, but multiple gear ratios including reverse gear cannot be achieved
Solution Approach 1:
The patent makes the planetary gear system multi-functional by enabling it to provide multiple gear ratios (forward gears and reverse gear) and different operating modes (direct drive, reduced gear, reverse) within a single stage. This is achieved by selectively locking or unlocking different components (sun gear, ring gear, carrier) to achieve various gear ratios without requiring multiple separate gear stages.
3Force
If high torque is required at the wheels for heavy vehicles, then the gear ratio must be increased, but this reduces the speed range where motors operate efficiently
Solution Approach 1:
The patent implements dynamic gear ratio adjustment by allowing the planetary gear system to switch between different gear ratios based on operating conditions. The system can dynamically select between direct drive mode (for high speed, low torque), reduced gear mode (for medium speed, medium torque), and reverse mode (for low speed, high torque), ensuring motors operate efficiently across the entire speed and torque range required for heavy vehicle applications.
Data Source
AI summary
The present invention provides a powertrain comprising a first electric motor (1), a second electric motor (2), a transmission assembly, a planetary gear (12) and a wheel drive axle (19), wherein the transmission assembly comprises a first input (5) connected to the first electric motor (1), a second input (3) connected to the second electric motor, and at least a first output (9) to which both the first electric motor (1) and the second electric motor (2) may provide torque, wherein the first input (5) is connectable to the first output (9) by a plurality of gear sets (7,10,8,11) being selectable by a first clutch assembly (15,17,101), and the second input (3) is connectable to the first output (9) by a plurality of gear sets (7,10,8,11) being selectable by a second clutch assembly (14,17,101′), to provide at least two gear ratios between the first output (9) and each of the first input (5) and the second input (3), wherein the gear sets and clutch assemblies are configured to allow a change between the two gear ratios without torque interrupt; and the planetary gear (12) comprises a sun gear (4), a ring gear (6) and a carrier (16), the carrier (16) is connected to the wheel drive axle (19) and the planetary gear (12) is shiftable between a first gear state, a second gear state and a third gear state, in the first gear state the ring gear (6) is kept rotationally stationary to provide a highest possible inherent gear ratio between the carrier (16) and the sun gear (4), in the second gear state a rotational speed of the ring gear (6) depends on the rotation of both the sun gear (4) and the carrier (16), and in the third gear state any two of the ring gear (6), the sun gear (4) and the carrier are kept rotationally constant to each other to provide a 1:1 gear ratio between the sun gear (4) and the carrier (16); and the first output (9) of the transmission assembly is coupled to the sun gear (4).